

   
\begin{tikzpicture}[scale=2.54]
% dpic version 2012.02.12 option -g for TikZ and PGF 1.01
\ifx\dpiclw\undefined\newdimen\dpiclw\fi
\global\def\dpicdraw{\draw[line width=\dpiclw]}
\global\def\dpicstop{;}
\dpiclw=0.8bp
\dpiclw=0.8bp
\dpicdraw (0,0)
 --(0,0.375)\dpicstop
\dpicdraw (0,0.5) circle (0.049213in)\dpicstop
\dpicdraw (-0.083333,0.5)
 ..controls (-0.083333,0.523012) and (-0.064679,0.541667)
 ..(-0.041667,0.541667)
 ..controls (-0.018655,0.541667) and (0,0.523012)
 ..(0,0.5)\dpicstop
\dpicdraw (0,0.5)
 ..controls (0,0.476988) and (0.018655,0.458333)
 ..(0.041667,0.458333)
 ..controls (0.064679,0.458333) and (0.083333,0.476988)
 ..(0.083333,0.5)\dpicstop
\dpicdraw (0,0.625)
 --(0,1)\dpicstop
\draw (0.125,0.5) node[right=-1.5bp]{$ v_{s}$};
\dpicdraw (0,1)
 --(0.375,1)
 --(0.395833,1.041667)
 --(0.4375,0.958333)
 --(0.479167,1.041667)
 --(0.520833,0.958333)
 --(0.5625,1.041667)
 --(0.604167,0.958333)
 --(0.625,1)
 --(1,1)\dpicstop
\draw (0.5,0.958333) node[below=-1.5bp]{$ R_{aux}$};
\draw (0.375,1) node[above left=-1.5bp]{$ +$};
\draw (0.5,1.041667) node[above=-1.5bp]{$ V_{x}$};
\draw (0.625,1) node[above right=-1.5bp]{$ -$};
\dpicdraw (1,1)
 --(1,0.625)
 --(1.041667,0.604167)
 --(0.958333,0.5625)
 --(1.041667,0.520833)
 --(0.958333,0.479167)
 --(1.041667,0.4375)
 --(0.958333,0.395833)
 --(1,0.375)
 --(1,0)\dpicstop
\draw (1.041667,0.5) node[right=-1.5bp]{$ R_{i} || R_{punta}$};
\dpicdraw (1,0)
 --(1,-0.125)\dpicstop
\dpicdraw (1.083333,-0.125)
 --(0.916667,-0.125)\dpicstop
\dpicdraw (1.055556,-0.15625)
 --(0.944444,-0.15625)\dpicstop
\dpicdraw (1.035714,-0.1875)
 --(0.964286,-0.1875)\dpicstop
\dpicdraw (1,0)
 --(0,0)\dpicstop
\end{tikzpicture}

